1. Field of the Invention
The present invention relates to a vehicle control system for managing vehicles travelling toward a worksite.
2. Description of the Related Art
In order to improve the efficiency of mining operations in a large scale mining area, the loaders (excavator, wheel loader), dump trucks, and so forth are made large in size. In other words, instead of running a plurality of dump trucks with a plurality of operators, attempts are being made to run a small number of dump trucks with a small number of operators by making the dump trucks larger. These dump trucks have reached the 200 t capacity class.
Particularly in recent years, unmanned dump trucks (unmanned vehicles) have come to be widely used with the dissemination of position measuring devices such as GPS (global positioning system) and human labor has been correspondingly reduced. In other words, a position measuring device such as GPS is deployed on the unmanned vehicle, compares the position measured with this position measurement device to the positions in the stored course data, and controls the vehicle so that these positions agree. The unmanned vehicle thereby travels along a predetermined course.
At the level to which unmanned vehicles were initially introduced, the unmanned vehicles performed work to transport ore from a predetermined loader to a predetermined earth removal site.
In a mining area, a plurality of loaders at a plurality of loading sites and a plurality of earth removal devices at a plurality of earth removal sites (hoppers for crushing and refining the ore and stockyards as temporary holding sites) are operating at the same time. For this reason, when any of the plurality of loaders and earth removal devices become unable to work temporarily for reasons such as a failure, it becomes necessary to provide orders for changing the travel route to the unmanned vehicles headed thereto. The change in the travel route is necessary in order to eliminate wasteful waiting time for the unmanned vehicles.
For example, a fleet 1 (group of unmanned vehicles) engaged in transport operations from an excavator A to a hopper B and a fleet 2 engaged in transport operations from an excavator C to a hopper D are working in parallel at the same time. Under these conditions, when the operator of the excavator A takes a break, it would be desirable for the unmanned vehicles in fleet 1 to shift to fleet 2, travel the travel route of fleet 2, and continue the transport operations without interruption.
A temporary work stoppage for one fleet and a loss of working efficiency often occur in cases other than when an operator takes a break. For example, a loader may engage in road maintenance at the loading site, making embankments for safety purposes, or making roads for the loader itself to travel upon during breaks from loading operations. In these cases as well, the operations for one fleet may be temporarily halted, causing reduced efficiency. Furthermore, the movement of a loader within the loading site, failure of a hopper, overflow, obstacles on the route traveled by the unmanned vehicles, and reductions in travel speeds of the unmanned vehicles due to quagmires on the travel route can temporarily halt work by a fleet and cause reduced efficiency.
In cases where there is a risk of reducing the efficiency of a fleet 1 in this way, the unmanned vehicles scheduled to perform work in the fleet 1 must be moved to another fleet 2, caused to take the travel route of the fleet 2, and sent to those loading sites and earth removal sites.
In the conventional art, a system is constituted wherein the travel route is changed once the unmanned vehicles have first traveled to a predetermined location. For example, the excavator A for fleet 1 temporarily stops work. The unmanned vehicles in fleet 1 continue to travel along the fleet 1 travel route and reach a predetermined location (for example, the entrance to the site where the excavator A is present). Then, at this predetermined location, the unmanned vehicles received instructions to xe2x80x9cchange to the fleet 2 travel routexe2x80x9d from a monitor station. According to these orders, the unmanned vehicles travel the fleet 2 travel route to the loading site (excavator C) for the fleet 2.
This type of technology is noted in the following reports.
For example, the Japanese Patent application Laid-Open No. 7-20939 (conventional art A) includes an invention wherein an unmanned transport vehicle traveling indoors is caused to move to and wait at a predetermined location (position of control information transmission device) on the transport path. At this waiting location, data for a changed transport path is provided to the unmanned transport vehicle.
Also, the Japanese Patent Application Laid-Open No. 10-181888 (conventional art B) includes an invention wherein a mobile machine is caused to travel to and wait at a mining site, and at this mining site, the mobile machine is provided orders for its next movements (movement to reentry path) depending on the current situation in the mining site (failure of loader or hopper).
Furthermore, in the Japanese Patent Application Laid-Open No. 8-263138 (conventional art C), an unmanned dump truck is caused to follow a travel course to a loading site and stop at the entry to the loading site. While stopped at this location, the vehicle generates data for a course from that position corresponding to the position of the loading machine and provides this course data to the unmanned vehicle.
This conventional art A, B, and C applies to cases wherein an excavator A temporarily stops work for a fleet 1. In this case, the unmanned vehicles in the fleet 1 must travel on the travel route for the fleet 1 and arrive at the entry for the loading site where the excavator A, that has temporarily stopped work, is located. It is then necessary for the unmanned vehicles to stop at the entry to the loading site and wait at this location for instructions from a monitor station. Then, after receiving the instructions changing the travel route from the monitor station, the unmanned vehicles must shift to the other fleet 2, follow the travel route for fleet 2, and go to the loading site (excavator C) for the fleet 2.
In this conventional art, it is not possible to change the travel route unless the unmanned vehicles have traveled to and stopped at a predetermined location. For this reason, the unmanned vehicles operate to no purpose and working efficiency is greatly reduced.
The present invention was made in view of these facts. It is a first object of the present invention to eliminate wasteful activity of the vehicles and to improve efficiency by making it possible to promptly change the travel route at the time when it becomes necessary to change the travel route of a vehicle.
The unmanned vehicles receive data for the scheduled travel route from the monitor station and travel along this scheduled travel route.
At the monitoring station, however, the decision is made whether it is necessary to change the initially provided travel route according to monitoring results. In this case, travel instructions are provided by the monitor station to the unmanned vehicle and instruct the unmanned vehicle to turn off at an intersection with the scheduled travel route and to follow the changed travel route. When the current position of the unmanned vehicle is sufficiently distant from the intersection, there is leeway for traveling and for performing navigation control and the unmanned vehicle can turn off at the intersection without leaving the travel route. However, when the current position of the unmanned vehicle is close to the intersection, there is no leeway for traveling and navigation control. For this reason there is a risk of the unmanned vehicle leaving the travel route near the intersection. Departure from the travel route (road surface leveled on one of two lanes for going back and forth) may bring about collisions with other vehicles, while increasing the risk of the vehicle overturning on the shoulder, or colliding with embankments or rock falls from cliffs.
The present invention was made in view of these facts. It is a second object of the present invention to definitely avoid leaving the travel route so as to avoid major accidents such as collisions with other vehicles, overturning, or landslides, even in the case where travel instructions to turn off at an intersection with the scheduled travel route are provided from the monitor station.
In a mining area, a plurality of vehicles arrive sequentially at a single worksite (for example, a loading site) and the loading work is performed in the order of arrival. The travel speed of manned dump trucks (manned vehicles) depends on the operator. For this reason, manned vehicles travel at any speed and arrive at the worksite in accordance with the operations by the operator. Also, unmanned vehicles travel at speeds and arrive at the worksite in accordance with speed data provided by the monitor station.
However, when another vehicle arrives at the worksite before a particular vehicle, that particular vehicle must wait at the worksite until the other vehicle""s work is complete.
Consequently, when the travel speed on a vehicle is set high and the vehicle travels to the worksite at a high speed, the early arrival results in a corresponding increase to the waiting time. For this reason, wasteful waiting time occurs for a particular vehicle and the efficiency is reduced by that waiting time. Moreover, when caused to travel at high speeds, a dump truck will have higher operating costs as well as wasteful waiting times. Specifically, wear on the tires is accelerated by the extent that the dump truck travels at high speeds to worksites. A dump truck uses special tires and the unit cost of the tires is very high. High speed travel increases wear on the tires and shortens the time between tire replacement. For this reason, the operating costs of the dump trucks become very high. Furthermore, fuel costs are increased due to the dump trucks traveling to worksites at high speeds. For this reason, fuel costs become high and also become a factor in raising the operating costs of the dump trucks.
It was thought that establishing low vehicle travel speeds would avoid these operating cost increases. However, even though the problem of increased dump truck operating costs is resolved when vehicles travel at those speeds, the time necessary to travel to a worksite is increased and work is started with the preceding vehicle having already completed its work. For this reason, wasteful free time, wherein loading work is not being performed at the worksite, occurs. The occurrence of this wasteful free time in conjunction with all of the vehicles traveling at low speeds results in a loss of working efficiency.
Before now, there have been no inventions for setting the speed of a particular vehicle in relation to another vehicle arriving at the worksite in advance thereof
The present invention was made in view of these facts. It is a third object of the present invention to be able to greatly increase working efficiency by starting work at a worksite in an optimum waiting time, while minimizing vehicle operating costs.
Moreover, Japanese Patent Application Laid-Open No. 11-126294 (conventional art D) is cited as showing the general technical level of this application. This report makes note of an invention wherein, when a plurality of automobiles enter an intersection, the path of each automobile is generated so that there is no conflict in the intersection. However, this conventional art D is only an invention for resolving the problem of conflict in an intersection. This point is different from the present invention which has the object of optimizing vehicle waiting times at a worksite, improving efficiency, and minimizing vehicle operating costs.
In order to achieve the abovementioned first object, the first invention relating to the present invention is a vehicle travel route control system applied to a case where a plurality of vehicles travel towards a plurality of worksites and perform works at the plurality of worksites, comprising: a monitor station for changing a worksite to which the vehicles should travel and providing to the vehicles data for a travel route to the changed worksite; and vehicles traveling along the travel route from their current positions to the changed worksite when the data for the travel route are provided from the monitor station,
wherein the monitor station changes the worksite to which the vehicles should travel on the basis of a result from monitoring current positions of the plurality of vehicles and current status of the plurality of worksites, and directly provides the data for the travel route from the current positions of the vehicles to the changed worksite on the basis of a result from monitoring the current positions of the plurality of vehicles and current status of the plurality of worksites; and
wherein the vehicles have position measuring devices for measuring the current positions of the vehicles, provide the current positions of the vehicles measured by the position measuring devices to the monitor station, and travel along the changed travel route from the current positions to the changed worksite when the data for the travel route are provided from the monitor station, while the vehicles are on any of the travel route of the vehicle.
In the first invention, the second invention is featured that the monitor station changes the worksite to which the vehicles should travel so as to maximize a working efficiency at the plurality of worksites.
In the first invention, the third invention is featured that the monitor station selects a travel route with a shortest travel time in a case where there is a plurality of travel routes from the current positions of the vehicles to the changed worksite.
The abovementioned first invention (second invention, third invention) is explained with reference to FIG. 1(b).
According to the first invention, the monitor station 20 changes the worksite to which the vehicle 30 should travel from worksite 60a to worksite 60axe2x80x2 based on the results of monitoring the current positions of the plurality of vehicles 30, 30xe2x80x2 and the current status of the plurality of worksites 60a, 60axe2x80x2, while providing to the vehicle 30 the data for the travel route from the current position of the vehicle 30 to the changed worksite 60a. When the data for the travel route are provided from the monitor station 20, the vehicle 30 travels along this travel route from its current position to the changed worksite 60axe2x80x2. 
In this way, with the first invention, the travel route of the vehicle 30 can be changed and the vehicle 30 can be caused to travel along the changed travel route at the time when a failure of the loaders 60 occurs at the worksite 60a and it becomes necessary to change the travel route of the vehicle 30. It is not necessary for the vehicle 30 to travel to, and stop and wait at the worksite 60a at which work is temporarily halted as in the prior art. The travel route can be changed at the current location while the vehicle 30 is traveling. For this reason, wasteful movement of the vehicle 30 is eliminated and the efficiency is greatly increased.
In order to achieve the abovementioned second object, the fourth invention relating to the present invention is a vehicle travel route control system comprising: a monitor station for changing a travel route that a vehicle should travel when the vehicle is traveling along a scheduled travel route toward a worksite and providing data for the changed travel route to the vehicle; and a vehicle for turning at an intersection of the scheduled travel route onto the changed travel route and traveling along the changed travel route when the data for the changed travel route are provided by the monitor station,
wherein, when the travel route is changed, the vehicle or the monitor station determines whether to travel along the scheduled travel route or the changed travel route after the intersection based on a distance from a current position on the scheduled travel route to the intersection; and
wherein the vehicle is an unmanned vehicle having a position measuring device for measuring a current position of the vehicle, which provides the current position of the vehicle measured by the position measuring device to the monitor and travels according to a result of the determination.
The abovementioned fourth invention is explained with reference to FIGS. 9(a) and 9(b).
According to the fourth invention, the vehicle 30, upon receiving the data for the changed travel route Kb from the monitor station 20, determines whether to travel along the scheduled travel route Ka or to travel along the changed travel route Kb after the intersection X based on the distance from the current position on the scheduled travel route Ka to the intersection X. This determination can also be made by the monitor station 20. The vehicle 30 travels according to the results of this determination. Specifically, when the distance is less than an established threshold value, the vehicle will travel along the scheduled travel route Ka after the intersection (FIG. 9(b)) because there is a risk of the vehicle leaving the travel route when turning at the intersection X. If the distance is greater than the threshold value, the vehicle will travel along the changed travel route Kb after the intersection (FIG. 9(a)) because there is no risk of the vehicle leaving the travel route when turning at the intersection X.
In this way, with the fourth invention, it becomes possible to insure the selection of the travel route having no risk of the vehicle leaving the travel route even when travel instruction to turn at the intersection X with the scheduled travel route Ka are received from the monitor station 20. For this reason, departure from the travel route is certainly prevented and major accidents such as collisions with other vehicles, overturning, or landslides are avoided.
In order to achieve the abovementioned third object, the fifth invention relating to the present invention is a vehicle control system applied to a case where a plurality of vehicles travel towards a worksite and the plurality of vehicles perform works in sequence at the worksite, comprising: a monitor station for providing to the vehicles data for a travel route to the worksite to which the vehicles should travel and data for a travel speed; and vehicles which, when the data for the travel route and the data for the travel speed are provided from the monitor station, travel along the travel route from their current positions to the worksite at the travel speed;
wherein the monitor station estimates a waiting time until the work begins for each vehicle based on a relationship between the current positions of the plurality of vehicles and a location of the worksite, and provides the data for the travel speed to each vehicle so as to be able to begin the work in an optimum waiting time based on a result of this estimate.
In the fifth invention, the sixth invention is featured that the monitor station finds an order of arrival at the worksite and an arrival time from the current position until arrival at the worksite for each vehicle, based on the relationship between the current positions of the plurality of vehicles and the location of the worksite, estimates a waiting time until the work begins for each vehicle, based on the order of arrival and the arrival time thus found and a working time required for one vehicle at the worksite; and generates data for the travel speed for each vehicle based on a result of this estimate so that the vehicles can arrive at the worksite in an optimum arrival time and can begin the work in the optimum waiting time.
The abovementioned fifth invention (sixth invention) is explained with reference to FIGS. 11(a) and 11(b).
With the fifth invention, in the monitor station 20, the waiting time Tw2, Tw3 until work begins is estimated for each vehicle 30xe2x80x2, 30 based on the relationship between the current positions G2, G3 of the plurality of vehicles 30xe2x80x2, 30 (FIG. 11(a)). Based on the results of this estimate, the data for speed of travel are provided to each vehicle 30xe2x80x2, 30 in order that work can begin in the optimum waiting times Tbw2, Tbw3. For this reason, the speed of travel of the vehicle 30, for example, is set at a lower speed and the vehicle travels at this low speed to the worksite. The vehicle 30 then can begin work in the optimum waiting time Tbw3 (FIG. 11(b)).
In this way, with the fifth invention, working efficiency can be greatly improved while the operating costs of the vehicles are minimized because the speed of travel of the vehicles is set so that work can begin in the optimum waiting time.